Australian reptile handlers say they have been stunned to rescue 102 venomous snakes from a backyard mulch pile in Sydney.

Cory Kerewaro said his business was initially called to rescue “a bunch” of the reptiles after one was reported to have bitten a dog at the property.

When his colleague arrived, he discovered 40 red-bellied black snakes – four of which gave birth to more live young once he had placed them in a removal bag.

Red-bellied black snakes are one of the most common venomous species in Australia but have not caused any human deaths on record.

The five adult and 97 baby snakes are currently under quarantine and will be released into a national park once the weather cools.

Mr Kerewaro said it was as record haul for the snake handlers, who normally catch between five and 15 reptiles per day.

He said he recalls colleague Dylan Cooper calling him within 15 minutes to say: “Mate, I’m going to be here a while. It’s a pretty big pile… I’m already over 15 snakes!”

“I thought he was stitching me up.”

The dog was “alive and well” after the incident which happened on Boxing Day, he added.

Female red-bellied black snakes often gather in small groups when they are ready to give birth, possibly to protect against predators, according to Mr Kerewaro.

They are the only snake of their genus to give live birth, the Australian Museum says on its website.

The species is considered to be shy, and bites – though uncommon – can cause swelling, nausea and diarrhoea.

Snake catchers are required by law to release the animals close to where they were found. But given the size this discovery, the catchers have been given permission to release the snakes into a national park away from human interactions.